The present invention relates to a capsule for preparing and delivering a beverage in a brewing device. The present invention more particularly aims at providing a capsule adapted to deliver brewed leaf tea although other beverages can be successfully brewed in the capsule.
Leaf tea ingredients are generally obtained from loose leaves that are chiselled or broken into small fragments. Brewing of these fragments can lead to the presence of large quantities of insoluble particles mixed with the infused solution. Therefore, when a capsule is designed specifically for delivering tea, it is important that it comprise filtering means. These filtering means should be adapted to let the liquid beverage freely out of the capsule, while simultaneously keeping all but a negligible amount of the undesirable ingredient particles inside the brewing enclosure.
European Patent application No. 05109566.9 describes several embodiments of a capsule adapted for brewing tea in a beverage machine. The capsule comprises a filtering wall delimiting one filtering side of the brewing enclosure. An overflow wall comprising at least one overflow aperture is positioned in the path of the brewed liquid after the filtering. In one particular embodiment, the filtering wall extends substantially from the bottom to the top of the enclosure. This arrangement provides a large filtering surface and thus favours a lower brewing pressure. Another feature of this particular embodiment is that the overflow wall is parallel to the filtering wall, and that an interstitial space separates the two walls. This configuration allows for the liquid that has gone through the filter to move upwards in the interstitial space until it reaches the overflow aperture. This aperture is sufficiently close to the top of the brewing enclosure. In this way, the beverage ingredients can be entirely submerged by the low pressure brewing fluid, while the flow rate from the capsule remains within the acceptable range.
The capsule described in European patent application No. 05109566.9 is based on a brewing principle that promotes the delivery of high quality tea. However, as previously described, the capsule comprises both a filtering wall and an overflow wall with an interstitial space between the two. It may further comprise a cover that faces the overflow wall. These features lead to a relatively complex structure that can be expensive to produce. Therefore, it would be desirable to provide a capsule based on the same or similar brewing principle but with a simplified, easier to manufacture and cheaper structure.